Lab Report

Purpose
Materials
Procedure
Data
Analysis
Conclusion
Sources of Error



Purpose Return to top



The purpose of this activity was to build and launch a model rocket
and apply concepts learned in class during the entire process.




Materials Return to top


  • Styrofoam
  • Estes rocket engines (B6-4 and C6-4) and igniter/ igniter plug
  • Old binder
  • Utility knife
  • 18" elastic
  • Hot glue and glue-gun
  • White glue
  • Scissors
  • Spray paint
  • Plastic bag
  • Wadding
  • Scotch tape
  • String
  • Paper clip
  • Dime roll
  • Cardboard
  • Plastic tube
  • Paper
  • Launch pad and launch controller
  • Estes altitude finder
  • Talcum powder
  • Straw



Procedure Return to top


Building Procedure:

Pieces resembling fins were cut out from an old binder and hot glued equidistant
to each other and parallel to the plastic tube. The engine mount was covered with glue
and stuffed inside the plastic tube. The one end of the elastic was glued inside the
plastic tube and the other end was attached to a nose cone shaped from a block of
styrofoam. A parachute cut from a plastic bag and tied with strings was glued to the
elastic. A straw was then glued onto the body tube to accommodate the launching device.
The parachute was powered with talcum, and then stuffed into the body tube.
The entire rocket was then spray-painted.

Launch Procedure:

An engine was placed into the engine mount. An igniter was placed into the clay
nozzle and held in place by an igniter plug. Alligator clips were attached to the igniter.
The rocket was placed on the launchpad, the launch button was then pressed.


Data Return to top

Launch Attempt 1:
Mass of rocket with B6-4 engine
0.0768kg
Time Up
4.57s
Time Down
13.4s
Angle
39°
Force of rocket engine (Estes)
6N
Time delay between the end of the thrust phase and ignition of the ejection charge
(Estes)
4s
Takeoff success
Yes
Controlled Takeoff
Yes
Recovery System Deploys
Yes
Broken Parts
No
Launch Attempt 2:

Takeoff success
Yes
Controlled Takeoff
Yes
Recovery System Deploys
Yes
Broken Parts
N/A (rocket could not be retrieved)




Analysis Return to top


Force of gravity
0.0768kg * 9.8m/s² = 0.753N
Net force on rocket
6N – 0.75N = 5.25 N
Distance travelled by rocket
50tan39° = 40.5 meters
Duration of thrust phase
4.57s – 4s = 0.57 seconds
Maximum velocity reached by rocket
F (∆t) = m (∆v)
5.25N(0.57s) = 0.0768kg(∆v)
2.993Ns = 0.0768∆v
∆v = 38.97 m/s
Acceleration reached during thrust phase
V₂ = V₁ + at
39.0 m/s = 0 +a (0.57s)
a = 68.42 m/s²
Velocity before hitting ground
40.5 = (V₂+0)/2 x (13.4)
40.5 = 6. 625 V₂
V₂ = 6.02 m/s
Acceleration after parachute deployment
6.02 = 0 + 13.4a
a = 0.44m/s
Force of air resistance after parachute deployment
Fnet – Fgravity = Fair
(0.44)(0.0768) – (0.0768)(9.8) = Fair
(0.0338)-(0.753)=Fair
Fair = 0.7188N
Fnet = 0.034N



Conclusion Return to top


Our rocket preformed well. It reached a maximum velocity of 39 m/s with an acceleration of
68.42 m/s² and the parachute deployed successfully on both trials, slowing it down to 0.44m/s².
Since the parachute was so effective, the rocket stayed intact for the first trial, and it was likely
it would stay intact for the second trial. However, since the second trial ended when the rocket
landed on the roof of a tall building, its condition is still unknown.


Sources of Error Return to top


The main source of error was the fact that the rocket did not launch perpendicular to the ground
but launched at an angle instead. This means the calculated distance will not be entirely accurate.
Another major source of error was air resistance and wind velocity; simply because it cannot be calculated with the
data we have. This means the values for acceleration during thrust phase, maximum velocity,
and net force on rocket will be higher than what they actually should be.


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